ITX-Llama - MIDI Options

The ITX Llama is equipped with several distinct options for MIDI playback, including genuine OPL-3 via an add-in module, on-chip emulated OPL-3 provided by the Crystal sound chip, Wavetable header for general MIDI add-on modules and a pair of headers for attaching a Raspberry Pi running mt32-pi for authentic Roland MT-32 support.

Below is a breakdown of each option and several add-ons that are compatible.

OPL-3 FM Synthesis Support

  1. Out of the box, the Crystal CS4237B sound chip can emulate OPL-3 through its Crystal FM synthesis engine. This is a close approximation to a genuine Yamaha OPL-3 for most titles but has been known to fall short in certain cases.
  2. The ITX Llama offers an OPL-3 header which accepts a custom OPL-3 board containing an old-stock Yamaha YMF262-M FM synth chip. This will provide a genuine Yamaha OPL-3 sound for games utilizing FM Synthesis.

Roland MT-32 Support

Raspberry Pi Zero 2

A Raspberry Pi Zero 2 is capability of emulating a Roland MT-32 using the excellent Munt emulator. To facilitate this as a drop-in feature, the mt32-pi project adds this functionality to a simple Pi Zero 2 and installed directly onto the ITX Llama. Audio is passed through an onboard DAC to the Crystal's Line In.

  • Pros:
    • provides a near perfect emulation of the Roland MT-32 / CM-32L (Intelligent Mode does require SoftMPU)
    • audio is routed through an onboard DAC to the Crystal sound chip via i2c preventing the need for additional hardware besides the Pi Zero 2 itself and an SD card.
  • Additional features:
    • mt32-pi supports General MIDI using the FluidSynth engine and user-supplied sound fonts. ITX Llama users could technically employ just the Pi Zero 2 with mt32-pi in addition to the OPL-3 module to cover nearly all bases of MIDI in early DOS games.
  • Installation:

Raspberry Pi 4

A Raspberry Pi 4 can also be attached in lieu of the Pi Zero 2. This is a much more advanced option but opens the possibility of running a full OS with Munt, FluidSynth and a modified version of the nuked-SC-55 emulator for genuine Roland SC-55 sound support.

  • A 40pin ribbon cable such as an old IDE cable affixed to the pins on board below and to the Raspberry Pi 4 is necessary to use this feature.
  • At this time, system setup for the Pi 4's OS is an advanced topic that is left up to the user to tinker with.
  • Pin Header: (below the female Pi Zero 2 header)

mt32pi Hardware UI

There are a set of headers that allow connecting the an mt32pi Hardware UI (OLED, 4 buttons, optional rotary encoder). This header is connected to the correct GPIO pins on the Raspberry Pi headers to simplify adding a control mechanism.

  • The header uses the following pins, which are wired one-to-one to an i2c OLED display: more info
    • SDA (data), SCL (clock), 3v3 (VCC), GND (ground)
    • Most OLED displays that specify i2c connections use these four pins.

  • The remaining pins are designed for either buttons or a rotary encoder. more info
    • B1 and B2 are "buttons" which control the Synth mode and ROM/Soundfont selection
    • B3 and B4 can either be "buttons" or a rotary encoder. These control the output volume of the synth engine.
    • A rotary encoder can be connected as follows:
    • B3 --> DAT
    • B4--> CLK
    • GN~D-->GND

Wavetable MIDI Support

  1. The ITX Llama contains a Wavetable compatible header as well. This can be configured with a variety of Wavetable Synth modules to provide General MIDI support through the Crystal sound chip.
    • This header can be enabled via Jumpers: J25, J26, J27

      • For using a Raspberry Pi (Zero2, 3 or 4) for converting MIDI to analog audio, place the three jumpers to the rightmost position ("PI").
      • For using a wavetable board, place the jumpers to the leftmost position ("WT").
    • NOTE: In Rev. F, the J27 "Power" jumper was removed. Power is now supplied to both the Wavetable header and the Pi GPIO pins simultaneously.

Wavetable Options

  1. Dreamblaster X8GS SE

    • Status: Tested, fully operational
    • General Specs:
      • 128 voice polyphony
      • 1024MB of flash memory for sample sets (divided into 7 banks)
      • "GS" modules include a read-only licensed Roland GS sample set
    • Links:
      • X8GS - High-end General Purpose MIDI Synth with customizable samples made exclusively for the ITX Llama

  2. Dreamblaster X2 SE / X2GS SE / X2TE

    • Status: Tested to fit
    • General Specs:
      • 81 voice polyphony
      • 64MB of flash memory for samples
      • "GS" modules include a read-only licensed Roland GS sample set
    • Links:
      • X2 SE - General Purpose MIDI Synth with customizable samples
      • X2GS SE - General Purpose MIDI Synth with customizable samples and an additional licensed Roland SC-55 sample set
      • X2 TE - "Tiny Edition" of the X2 SE

  3. Dreamblaster X16 / X16GS

    • Status: Will only fit without a Pi Zero 2 installed
    • General Specs:
      • 256 voice polyphony
      • 1024MB of flash memory for sample sets (divided into 7 banks)
      • 8MB SDRAM for very high quality DSP effects
      • "GS" modules include a read-only licensed Roland GS sample set
    • Links:
      • X16 - High-End General Purpose MIDI Synth with customizable samples
      • X16GS - High-End General Purpose MIDI Synth with customizable samples and an additional licensed Roland SC-55 sample set